1. Technical Field
This disclosure relates to digital optical switch arrays, and in particular to tapered waveguide S-bend interconnects for digital switch arrays.
2. Description of the Related Art
Digital optical switches (DOS) and switch arrays are increasingly replacing other types of optical switching devices in a wide variety of applications, including communication systems.
Conventional DOS with no shaping; i.e. having only a single small angle, are typically very long. Such long length can contribute to unacceptable propagation losses, and can also lead to reduced fabrication yields. Switch arrays including such conventional DOS as Y-branch waveguide switches can be connected with S-bend interconnects with acceptable radii of curvature; i.e. waveguides shaped like an "S" having optical propagation losses that are not substantially increased. However, by employing such conventional DOS, such switch arrays are also very long, and therefore are not attractive.
Typically, there is an appreciable amount of overlap of branches in a conventional DOS, which contribute to the overall length of the DOS. For example, about two-thirds of the length of a switch array using DOS can be attributed to overlap of branches.